Objectives: 1. To develop a new method for predicting nutrient retention in thermally processed foods which heat by conduction. 2. To develop a procedure for estimation of the kinetic parameters describing the response of a nutrient to thermal energy. 3. To develop a method for predicting the nutrient retention in thermally processed foods which heat primarily by convection. Methods: Recently Lunt et al. (1972) reported a method of estimating thermal process time for accomplishing lethality in canned foods. This method has been extended so that it may be used to estimate average nutrient retention of any conduction-heating food for which a reference reaction rate constant (Kr) and an Arrhenius activation energy (E) is known. The method will be further developed to include process variables such as steam temperature and container or food geometry. The method will alos be used to estimate the kinetic parameters Kr and Ea of a nutrient by using the procedure in reverse order. That is, instead of trying to predict the mass average concentration of nutrient remaining, such nutrients as vitamin B6, thiamine and pantothenic acid will be determined in such products as pureed peas and pureed tomatoes following a given heat treatment. Then knowing the mass average percent nutrient retention and the process variables, the charts developed earlier can be used to estimate Kr and Ea. This involves a trial and error procedure and requires much less experimental work than existing methods. For convection heated foods, the experimentally determined temperature profiles in containers will be used with Kr and Ea values to develop a procedure for predicting mass wverage retention of any food component (e.g. nutrient, quality factor, enzyme, or microorganism)